# CVE-2020-3168: Cisco Nexus 1000V Switch for VMware vSphere Secure Login Enhancements Denial of Service Vulnerability

> Unauthenticated remote attackers can cause a denial of service on Cisco Nexus 1000V VSM by exhausting resources via failed CLI logins when Secure Login Enhancements are enabled.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Feb 2020
- **Updated:** 15 Nov 2024
- **Also known as:** GHSA-qqf9-xgg2-qrxx

## What is CVE-2020-3168?

CVE-2020-3168 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 26 Feb 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Secure Login Enhancements capability of Cisco Nexus 1000V Switch for VMware vSphere could allow an unauthenticated, remote attacker to cause an affected Nexus 1000V Virtual Supervisor Module (VSM) to become inaccessible to users through the CLI. The vulnerability is due to improper resource allocation during failed CLI login attempts when login parameters that are part of the Secure Login Enhancements capability are configured on an affected device. An attacker could exploit this vulnerability by performing a high amount of login attempts against the affected device. A successful exploit could cause the affected device to become inaccessible to other users, resulting in a denial of service (DoS) condition requiring a manual power cycle of the VSM to recover.

Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-399

## Which versions are affected by CVE-2020-3168?

It affects 1 product.


Products: Cisco Nx-Os.

## How do I fix CVE-2020-3168?

No fix has been published for CVE-2020-3168 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3168 being exploited?

There is no known exploitation of CVE-2020-3168 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Nx-Os

- [CVE-2024-20399](https://insights.sbomify.com/CVE-2024-20399/): Cisco NX-OS Command Injection (medium 6.0, exploited in the wild)
- [CVE-2021-1361](https://insights.sbomify.com/CVE-2021-1361/): Cisco NX-OS Software Unauthenticated Arbitrary File Actions Vulnerability (critical 9.8)
- [CVE-2018-0301](https://insights.sbomify.com/CVE-2018-0301/): Memory corruption in Cisco NX-OS unknown (critical 9.8)
- [CVE-2016-1453](https://insights.sbomify.com/CVE-2016-1453/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-1341](https://insights.sbomify.com/CVE-2016-1341/): Hardcoded credentials in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-3168 and fix it if it is affected.

What it is: CVE-2020-3168 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 26 Feb 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-3168 in the wild and no public exploit code.

Affected product: Cisco Nx-Os. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-3168/ (Markdown: https://insights.sbomify.com/CVE-2020-3168/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3168
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3168
- OSV: https://osv.dev/vulnerability/CVE-2020-3168

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-3168/
Summaries are generated and may contain mistakes; the official description above is the record.